1. Field of the Invention
This invention relates to motion compensated video signal processing.
2. Description of the Prior Art
Motion compensated video signal processing is used in video signal processing applications such as television standards conversion, film standards conversion or video to film conversion. An example of a previously proposed motion compensated video processing apparatus is described in the British Published Patent Application number GB-A-2 231 749, in which pairs of temporally adjacent images (fields or frames) of a digital video signal are processed to generate corresponding sets of motion vectors. The processing is carried out on discrete blocks of the images, so that each motion vector represents the inter-image motion of the contents of a respective block.
Each set of motion vectors is then supplied to a motion vector reducer which derives a subset of the set of motion vectors for each block, which is then passed to a motion vector selector which assigns one of the subset of motion vectors to each picture element (pixel) in each block of the image. The selected motion vector for each pixel is supplied to a motion compensated interpolator which interpolates output images from the input images, taking into account the motion between the input images.
Motion compensated video signal processing such as that described above requires powerful and complex processing apparatus to carry out the very large number of calculations required to generate and process motion vectors for each pair of input images. This is particularly true if the images are in a high definition format, or if the processing is to be performed on an input video signal to produce an output video signal in real time, in which case multiple sets of identical apparatus may be operated in parallel in order to generate sets of motion vectors for each output image in the time available (e.g. an output field period).